As someone who teaches and writes in administrative law, I approach the U.S. Court of Appeals for the Fourth Circuit’s transgender bathroom decision (which was just stayed by the Supreme Court) with a focus on the court’s treatment of relevant AdLaw principles. A key part of the Fourth Circuit’s conclusion that the Gloucester County School Board engaged in unlawful discrimination “on the basis of sex” against the transgender student relies upon the federal government’s interpretation of its own regulations implementing Title IX, as expressed in a guidance letter issued by the Department of Education. Pursuant to a case called Auer v. Robbins, the Fourth Circuit concluded, this interpretation was due controlling weight. Yet the Fourth Circuit got this part of its analysis completely wrong. As I explain in more detail at the Volokh Conspiracy, the federal government’s interpretation was not due an deference at all as it did not represent an elaboration or explanation of the relevant statutory language. Instead, it simply parroted the relevant statutory language, and the feds never bothered to do those things necessary for their statutory interpretation to get any deference at all. So even if one were to disagree with Ed’s analysis of the merits, the Supreme Court would be fully justified in reversing the Fourth Circuit for its faulty analysis.